The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some of such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
With the ever increasing demand for better capacity, increasing data rates and higher quality services in the world of mobile communications comes ever increasing demand for better performance of cellular network infrastructures. The available frequency resources are limited and need for efficient use of the resources is essential. The need for more efficient usage of radio resources has brought out an idea of increasing the number of cells available for mobile user terminal by employing small cells having coverage inside buildings. In large buildings there might be two to four base stations serving one floor. In large buildings having many floors this may lead into situations where there may be hundreds base stations in a relatively small geographical area. Outside the building(s) there may be a macro cell serving a large geographical area.
The above situation is challenging regarding handovers when user terminals are moving from the coverage area of the macro cell to the buildings which are served by a large number of base stations.